1. Field of the Invention
The present invention pertains to wafer-type valves, such as butterfly valves. Such valves typically include a relatively thin, generally cylindrical valve body which is connected to a pipeline by being clamped between two flange fittings. The valve body has a flowway therethrough and a valve element, generally disc-shaped, which is mounted in the flowway for movement from a closed valve position to an open valve position. The present invention comprises an adapter device for adapting the valve body to various types of flange fittings in a pipeline. Furthermore, the valve body includes an annular seat located between the disc-shaped valve element and the valve body. This seat is held in place by a seat retainer plate. This invention also pertains to mounting of this seat retainer in position on the valve body.
2. Description of the Prior Art
In the past, some wafer valves of the type described above have had holes formed in their valve bodies for receipt of stud members such as bolts which extend between the flange fittings in order to clamp the valve therebetween. The placement of the studs through the holes in the valve body serves to center the valve in place until the flange fittings can be firmly secured.
Problems arise in that the various flange fittings with which a particular type of valve will be used are not uniform. In particular, the size, number, and spacing of the stud members vary. In the past, it has been necessary to manufacture valves of one basic type in a number of forms each designed to be used with a particular type of flange fitting. The manufacture of various forms of a single type of valve body is not only unduly expensive, but still fails, in at least some cases, to ensure that all the types of flange fittings which may be encountered in the field can be properly accommodated.
A number of attempts have been made in the past to accommodate the various types of flange fittings without changing the form of the valve body. One such technique has been to cast lugs onto the valve body in correspondence with individual bolt pattern of the flange fitting with which that valve is to be used. Another solution has been to cast a flanged connection area onto the valve body and drill holes to accommodate the specific flange requirements. None of these solutions offer the advantages and flexibility of the present invention. In each of these above-mentioned solutions, the valve body, once adapted by casting and/or drilling of appendages, is suitable for one flange standard only. None of these solutions make one given valve body compatible with the various International Flange Standards.
There are three U.S. patents which disclose means for adapting a standard valve body to various flange fittings. U.S. Pat. No. 4,079,746 shows a valve assembly in which the adapter has a generally circular central area which has a central opening for the non-interfering receipt of the rotary valve stem extending from the valve body. As distinguished from the present invention, this device is adapted for valve bodies having no integral formations with bolt-receiving holes. While suitable for this type of valve, the device of the U.S. Pat. No. 4,079,746 patent is more bulky, complex in configuration and cumbersome than is necessary or desirable for valves whose bodies form their own bolt holes.
U.S. Pat. No. 3,722,855 discloses a between-flange valve assembly and clamping assembly. In this device, the flanges are interchangeable so that any given valve structure can have various flanges on different ends. The flanges are internally threaded union members for engaging threaded pipes and other fittings. Interchangeable clamps lock around the flanges.
U.S. Pat. No. 4,101,112 also discloses a pipeline coupling system. This patent discloses reusable clamps between a wafer-type butterfly valve assembly and pipe flanges. Like the devices of the two prior patents, this device involves an adapter which is unduly complex for certain types of valve bodies.